Photographic Observations of the Minor Planet (1) Ceres in Tashkent in 1951–1994

A procedure is described for remeasuring photographic plates with images of the minor planet (1) Ceres obtained in 1951–1994 with the Tashkent normal astrograph. To determine the observed spherical coordinates, the PPM catalog, based on the FK5 system, was used as a reference catalog. The calculation of the orbit of the minor planet (1) Ceres and the determination of the PPM zero-points and periodic errors on the basis of these observations yielded a unit weight error of 0.270. The derived coordinates and velocity components of (1) Ceres for J.D. = 2441600.5 are presented together with PPM zero-point and periodic-error-coefficient corrections. One of the results of the work is the high precision of the remeasured images, which makes it possible to use these observations, along with no less accurate observations of other selected minor planets, for determining corrections to the stellar coordinate system.     

Nikmelnikovite,Ca 12 Fe 2+ Fe $$_{3}^{{3 + }}$$ Al 3 (SiO 4 ) 6 (OH) 20 : A New Mineral from the Kovdor Massif (Kola Peninsula,Russia)

Doklady Earth Sciences - Nikmelnikovite, Ca12Fe2+Fe$$_{3}^{{3 + }}$$Al3(SiO4)6(OH)20, a new mineral from the Kovdor massif (Kola Peninsula, Russia), is described. It is the first trigonal...